1. Technical Field
The present invention relates to a switch device for use in controlling a plurality of electrical circuits.
2. Background Art
JP 2012-134030 A and JP 2003-177871 A describe, as a switch device for use in control of a plurality of electrical circuits, a switch device including a touch sensor which an operator can touch with their finger for inputting information, as an input unit.
In the switch device described above, as input is accepted even if the operator touches the touch sensor by mistake, there is a possibility that a control operation which is not desired by the operator will be performed for the electrical circuits.
JP 2007-317393 A discloses a switch device capable of inhibiting control of the electrical circuits which is against the operator's intention, caused by the operator's erroneous touching of the touch sensor. This reference describes a switch device including an operation plate on which a plurality of operation indications are described, a plurality of touch electrodes configured to output a proximity signal representing the operation indication touched by the operator, a press switch which is depressed to output a press signal, and a control section configured to output a command signal to an electrical circuit. The touch electrodes are provided integrally with the operation plate and corresponding to the respective operation indications. The press switch is depressed by the operator pressing the operation plate. The control section identifies the input of a proximity signal only upon the input of the press signal and outputs a command signal to the electrical circuit based on the identified proximity signal.
In the switch device described in JP 2007-317393 A, in which the touch electrodes are integrally formed with the operation plate, the touch electrodes move with the operation plate when the operator presses the operation plate. However, in order to allow the simultaneous movement of the operation plate and the touch electrodes, the touch electrodes cannot be fixed to the circuit board. Accordingly, in the switch device described in JP 2007-317393 A, it is necessary to connect between the circuit board and the touch electrodes with a flexible harness or a flexible substrate, which results in an increase in the number of components and an increase in costs.
Further, as a force required for pressing the touch electrodes varies depending on the handling state of the harness or the flexible substrate, such a force may vary for each switch device due to the manufacturing accuracy at the time of mass production.
Also, in order to prevent the harness or the flexible substrate being broken by pressing the touch electrodes repeatedly, high durability is required for each component. In addition, as the harness or the flexible substrate would be hardened due to a change over time, the sense of operation perceived by the operator when pressing the touch electrodes may change after using the switch device for a long time.
The advantage of the present invention is therefore to provide a switch device for use in controlling a plurality of electrical circuits, in which touch electrodes can be fixed to a circuit board without the use of a harness or a flexible substrate, and the number of components can be reduced.